PORTLAND, Maine — Four years ago, Chris Martin was working in the warehouse at Texas Appliance in his native Arlington, Texas.

His promising pitching career had been curtailed by a torn labrum in his shoulder when he was at McLennan Community College. He had undergone surgery to repair it but when he was unable to pitch, he lost interest in school and stopped attending classes.

That led him into the workforce.

Martin tried to make a comeback in an independent league but the repaired shoulder still bothered him so he decided to hang up his spikes and went to work at UPS and then Texas Appliance.

While working at the warehouse, he began playing catch with his boss and high school buddy Jordan Bostick.

“My arm started to feel good and [Bostick] suggested that I try out for an independent team,” said Martin, who did just that.

In 2010, he hooked up with Grand Prairie of the American Association, where he pitched for former major leaguer and Oklahoma State star Pete Incaviglia, who was the manager.

The 6-foot-7, 225-pound Martin went 4-0 with a 1.96 earned run average and 36 strikeouts in 36 2/3 innings.

“Incaviglia was a great guy,” said Martin, who was contacted by the manager after the season and told the Boston Red Sox wanted to “check me out.”

He went to extended spring training with the Red Sox in 2011 and signed a minor league contract on March 15.

He pitched for Class A Greenville (South Atlantic League) and Salem (Carolina League) and made three appearances for the Portland Sea Dogs of the AA Eastern League that year.

Last season, he spent the year in Portland and was 3-6 with a 4.48 ERA in 23 appearances (12 starts) and 76 1/3 innings.

He had a productive fall baseball campaign in Surprise, Ariz., and he is off to a terrific start this spring in Portland.

Martin is 1-0 with one save in four relief appearances spanning 11 innings. He has given up just six hits and has struck out 15 while walking just two. He was the Eastern League’s Pitcher of the Week last week.

Martin said Thursday that even when he was working at UPS and Texas Appliance, he never lost his desire to pitch again.

“I thought about it all the time,” said Martin. “I saw friends and guys I grew up with playing in the big leagues. I felt I was just as good as they were and I could be in their shoes.”

And that could happen if he continues to pitch the way he has.

“He has become very, very comfortable with his body and his delivery,” said Sea Dogs pitching coach Bob Kipper. “His body helps him create the angle. His delivery enables him to expose the baseball late. Thatt makes his pitches more deceptive. The hitter has less time to see the ball.”

Martin has a three-quarter-arm delivery and throws his four-seam fastball in the 93-95 mph range.

Martin said it is his slider, which he refined during the Arizona fall league, that has been pivotal to his success.

“I’ve always thrown hard and I got away with my fastball in ‘A’ ball. So I moved up real quickly to ‘AA.’ But you have to have a second pitch in ‘AA,’” said the 26-year-old Martin. “I didn’t have very good command of my slider last year and it hurt me.”

So he went to work on it in the fall.

“I’ve got command of it now. It’s a lot tighter and it breaks later,” said Martin. “And I’ve been able to keep it down in the zone consistently.”

His slider usually clocks in at 84-86 mph, he said.

“His slider has improved dramatically,” said Kipper.

Martin said the Arizona League proved to be a “great experience for me” and he also said Kipper has been helpful in his development.

“He is a tireless worker and he is also a good athlete,” said Kipper, noting that he made an exceptional play charging off the mound to field a bunt and throw the runner out in their 1-0 win over Binghamton on Wednesday night.

Martin is continuing to work on a split-fingered fastball.

“When I was a starting pitcher, you needed a third pitch to keep hitters off-balance,” said Martin. “But when it’s cold like it has been, I haven’t had a feel for [the split-fingered fastball]. I’ll put it in the mix when the weather warms up.”

Martin has been understandably pleased with his start and he said he loves playing in Portland.

“After you get through the first two months of weather, it’s beautiful up here,” said Martin.

He is often reminded of his days in the workforce.

“During spring training, the Red Sox strength and conditioning coach [Pat Sandora] asked me what the best dryer was,” said Martin. “And [pitcher] Chris Hernandez bought a new house and asked me what appliances to buy.”

He quipped that when he’s able to buy a house, he’ll know what appliances to purchase.

If he keeps pitching the way he has been, he’ll someday be able to afford a new house and the best appliances money can buy.